This invention relates to conveyor scrapers used to remove particulate conveyed material from belt conveyors. Scrapers are typically employed at the head pulley end of a conveyor, where the bulk of the conveyed material is discharged from the conveyor. However, in many applications a residual film or layer of conveyed material clings to the belt after the usual discharge point. Typically, the residual material comprises the finer elements of the material being conveyed. A high moisture content in the conveyed material increases the difficulty of removing residual material from the belt. This is often the case in mining operations and similar applications.
Devices for cleaning a belt conveyor are well-known. These devices typically employ a scraper blade which contacts the belt surface and acts as a barrier to residual material as the belt moves past the scraper blade. It is desirable to make the scraper blade of a material which is softer than the conveyor belt so that the unavoidable wear is primarily taken by the scraper blade rather than the more expensive belt. However, this effort to avoid damaging the belt can lead to inefficient belt cleaning as the scraper blade becomes worn away. Frequent adjustment of the scraper blade position and periodic replacement of scraper blades decreases cleaning efficiency and increases down time.
It is an object of this invention to provide a scraper blade having increased useful life together with increased cleaning efficiency.
Another object is to provide a scraper blade which utilizes a limited quantity of the conveyed material to provide a wearing surface for the blade.
Another object is to provide an improved scraper blade which readily accommodates a substantial range of different belt widths.
Accordingly, the invention is directed to an improved scraper blade for a scraper employed to clean particulate conveyed material from a belt conveyor. The scraper is mounted on a scraper shaft having its opposite ends supported in a pair of tensioning supports located at opposite sides of a conveyor belt. The scraper shaft extends across the conveyor belt in spaced relation thereto. The scraper blade itself comprises an elongated block of molded elastomer material mounted on the scraper shaft. The scraper blade has a leading edge extending across and engaging the conveyor belt at one transverse position and a trailing edge extending across and engaging the conveyor belt at a second transverse position spaced from the first position. The surface of the blade intermediate its leading and trailing edges has a shallow concavity of curved configuration spaced from the belt. The depth of the concavity is only sufficient to collect a limited quantity of particulate conveyed material therein. This trapped conveyed material acts as a wearing surface that extends the useful life of the blade.